This invention relates to new and useful improvements in heat exchangers, particularly heat exchangers designed for use in buildings having a very moist interior environment such as animal barns and the like. Buildings in which animals are housed in fairly large numbers often suffer from an overheated moist atmosphere and unless the temperature and humidity are rigidly controlled, disease is often prevalent. Examples are chicken raising establishments, pig barns and even cattle barns.
In relatively warm weather, control is relatively easy because the outside ambient temperature is such that free circulation can be obtained merely by opening windows and the like within the building but with an outside ambient temperature which is very cold such as in northern climates, heat exchangers have to be utilized.
Normal heat exchangers used for this purpose merely exhaust inside air through a core and draw cold outside air through opposing channels so that heat is picked up by the outside air from the exhausting air prior to the exhausting air being discharged. Due to the extremely high humidity of the exhausting warm air, a considerable amount of moisture is carried thereby and the heat exchanging core often drops the temperature of this air below the dew point thus causing the water or moisture to condense and with cold outside air passing through the heat exchanger, severe frosting often occurs. This frosting is so severe that the heat exchanger becomes inoperative unless defrosting takes place.
Conventional heat exchangers defrost by reversing the flow of air by routing the inside air through the incoming air channels. Inasmuch as this inside air is often contaminated, the channels normally carrying the fresh outside air also become contaminated. Furthermore particle deposition can take place with the subsequent reduction of cross-sectional area of channels normally carrying the clean air inwardly.
Various methods for defrosting have been proposed but all these methods add complication and inefficiency. Attempts have been made to manufacture a heat exchange apparatus of this type which is substantially free from frosting problems but to date have not met with success.